De echoscopie in de verloskundige zorg

Rede uitgesproken bij de aanvaarding van het ambt van gewoon lector in de Gynaecologie en Verloskunde in het bijzonder de methoden tot foetale bewaking voor en tijdens de baring aan de Erasmus Universiteit te Rotterdam op woensdag 1 maart 197

Assessment of fetal left cardiac isovolumic relaxation time in appropriate and small-for-gestational-age fetuses

Left ventricular isovolumic relaxation time was studied in 22 appropriate-for-gestational-age fetuses (AGA, 26–40 wk) and 12 small-for-gestational-age fetuses (SGA, 29–37 wk). Left ventricular isovolumic relaxation time was determined from the interval between aortic valve closure and maximal left atrial dimension by M-mode, and from the interval between aortic valve closure artefact and onset of transmitral flow by pulsed Doppler. Mean left ventricular isovolumic relaxation time by M-mode (36 ± 6 ms) and by pulsed Doppler (49 ± 10 ms) were significantly different (p < 0.05) in AGA while this was not so in SGA (56 ± 10 ms vs. 60 ± 8 ms). A significant difference (p < 0.05) in mean left ventricular isovolumic relaxation time by M-mode existed between AGA (36 ± 6 ms) and SGA (56 ± 10 ms), whereas this was not so for pulsed Doppler (48 ± 10 ms vs. 60 ± 8 ms). Mean left ventricular isovolumic relaxation time by Doppler was significantly larger (mean difference 14 ± 8 ms; p < 0.05) than by M-mode in AGA. However, there was no difference in mean left ventricular isovolumic relaxation time between the two ultrasound modalities in SGA. These data suggest synchronization of mitral cusp separation and transmitral blood flow in the SGA fetus. We speculate that, in the SGA fetus, delayed left ventricular isovolumic relaxation time may reflect cardiac diastolic dysfunction

Effect of physiological heart rate changes on left ventricular dimensions and mitral blood flow velocities in the normal fetus

M-mode echo recordings of the left ventricle (LV) and inflow LV Doppler velocimetry were performed in nine normal fetuses at a gestational age of 36–39 weeks. In each fetus ∼ 80 consecutive cardiac cycles were digitized. The duration of each cardiac cycle (T) and the corresponding end-diastolic (EDD), end-systolic (ESD) dimensions of LV or the peak velocity of early (E) and late atrial (A) mitral flow parameters was calculated. The role of sonographic parameters on current (Tn) and preceding (Tn − 1) cardiac cycles was assessed using linear regression. Significant dependency of ventricular EDD and transmitral A peak velocity upon Tn was demonstrated. We speculate that atrial systole has an important role to play in the beat-to-beat regulation of fetal stroke volume

Doppler colour flow mapping of fetal intracerebral arteries in the presence of central nervous system anomalies

The adjunctive role of Doppler colour flow mapping in the evaluation of intracerebral morphology and arterial blood flow in the presence of normal and abnormal central nervous system morphology was determined. A total of 59 fetuses with suspected central nervous system pathology between 14 and 37 weeks of gestation was studied (median 31 weeks). One hundred and one fetuses with normal central nervous system anatomy between 14 and 37 weeks (median 19 weeks) served as controls. Visualisation of blood flow in one or more intracerebral arterial vessels was successful in more than 80% of normal fetuses. For the anterior, middle and posterior cerebral artery, the percentages were 63%, 89% and 45%, respectively, at 14–25 weeks and 74%, 100% and 55%, respectively, at 26–37 weeks of gestation. Intracerebral arterial flow identification was attempted in 52/59 (88%) affected fetuses. Identification of blood flow in one or more intracerebral arterial vessels was successful in (77%) fetuses. End-diastolic flow velocities were present in at least one of the intracerebral arteries in fetuses, absent in one case of hydrocephaly and raised in the presence of an intracerebral vascular tumour. Doppler colour flow mapping seems to provide only limited additional information on intracranial structural pathology

Doppler flow velocity waveforms in the fetal cardiac outflow tract: Reproducibility of waveform recording and analysis

__Abstract__ Reproducibility of flow velocity waveform recording and analysis was studied at fetal cardiac level (ductus arteriosus, pulmonary artery and ascending aorta) in 42 normal pregnancies. The flow velocity parameters studied were the peak systolic velocity (PSV), acceleration time (ACT), acceleration velocity (ACV), average velocity (AV) and flow velocity integral (FVI). In each patient, two consecutive measurements were performed (time delay 15 min) and of each measurement two hardcopies were analysed. A high reproducibility was achieved for the PSV, AV and FVI in all vessels studied; the coefficients of variation between readings of hardcopies were ≤3%, and the coefficients of variation between tests within patients were ≤7%. A moderate reproducibility was achieved for the ACT in the ascending aorta and pulmonary artery; the variation between tests was large for the ductus arteriosus. The reproducibility of the ACV was poor

Three-dimensional sonographic measurement of normal fetal brain volume during the second half of pregnancy

Objectives: This study was undertaken to develop a three-dimensional (3D) ultrasound method of measuring fetal brain volume. Study design: Serial 3D sonographic measurements of fetal brain volume were made in 68 normal singleton pregnancies a

Effect of fetal breathing movements on fetal cardiac hemodynamics

__Abstract__ Maximum flow velocity waveforms were studied at atrioventricular and outflow tract level in 12 cases during fetal breathing activity and in 12 cases during fetal apnea matched for maternal and gestational age and maternal parity. Gestational age ranged between 27 and 40 weeks (median 30 weeks). All flow velocity waveforms were obtained using a mechanical sector scanner with a pulsed Doppler system (carrier frequency 3.5 MHz). Time-averaged flow velocities were clearly different between inspiration and expiration at all four recording levels, reflecting changes in venous return as a result of fluctuations in intrathoracic pressure during fetal breathing activity. Percentage change between inspiration and expiration at outflow tract level was positively correlated with gestational age. Time-averaged flow velocity at mitral level and ascending aorta level was significantly higher during fetal breathing activity than during apnea, suggesting increased shunting of blood flow through the foramen ovale. Acceleration time at outflow tract level demonstrated very little change relative to inspiration and expiration